In the case of grid accelerators, the positively charged ions are drawn from a plasma by means of a grid arrangement, in which a first grid that borders on the plasma chamber lies at an anode potential, and a second grid, offset in the beam exit direction, lies at a more negative cathode potential, and electrostatically accelerated between the two grids. Such an arrangement is known from U.S. Pat. No. 3,613,370, for example. The ion stream density of such an accelerator arrangement is limited to low values due to spatial charging effects.
Another design provides a plasma chamber through which an electric field for accelerating positively charged ions in the direction of a beam exit opening, for one thing, and a magnetic field for guiding electrons that serve to ionize a neutral working gas, for another thing, pass. In particular, accelerator arrangements having a ring-shaped plasma chamber, in which the magnetic field runs predominantly radially and electrons move on closed drift paths under the influence of the electric and magnetic fields move on closed drift paths under the influence of the electric and magnetic fields have been in use for some time. Such an accelerator arrangement is known, for example, from U.S. Pat. No. 5,847,493.
An embodiment of a pulse plasma accelerator, as it is known from DE 15 39 264, for example, which deviates significantly from this, both theoretically and practically, provides electrode rails at opposite sides of a flat plasma channel, between which a current flows crosswise to the longitudinal direction of a channel, in a working gas that is located in the channel, by means of pulsed discharges, thereby creating a plasma. The current loop with electrode rails and current through the plasma chamber results in pulse-like ejection of the ionized gas, by means of magnetic displacement.